1. Field of the Invention
The present invention relates generally to a digital broadcasting reception terminal, and more particularly to a digital broadcasting reception terminal for receiving digital broadcast data based on a digital video broadcasting-handled (DVB-H) scheme and a channel change method of the same.
2. Description of the Related Art
Digital broadcasting generally refers to a broadcasting service which provides users with a high-definition image and high-quality sound and improved service over conventional analog broadcasting. There are various types of digital broadcasting, including digital multimedia broadcasting (DMB), digital audio broadcasting (DAB), digital video broadcasting (DVB), MediaFLO, and digital video broadcasting-handled (DVB-H).
The DVB-H broadcasting system uses an Internet protocol data casting (IPDC) scheme, which broadcasts data including audio and video (AV) data after compressing the broadcast data in a packet unit, such as in the wire/wireless Internet. According to the DVB-H broadcasting scheme, the packetized broadcast data according to each channel are multiplexed in a time slicing multiplexing data transmission method. The time slicing multiplexing method slices the capacity of a transmission path into time slots (i.e., time intervals) which carry the packetized broadcast data.
FIG. 1 is a view illustrating digital broadcast data broadcasted in a conventional DVB-H broadcasting system.
It is assumed in FIG. 1 that the DVB-H broadcasting system has five broadcasting channels, that is, channels A, B, C, D and E. In this case, a broadcasting station packetizes broadcast data according to channels, and periodically broadcasts resultant packet data according to a channel sequence. As a result, a broadcasting station in the DVB-H broadcasting system broadcasts data of each channel based on a period of time, as shown in FIG. 1. Then, a digital broadcasting reception terminal decodes information about a starting time when broadcast data of a channel selected by the user from among the entire broadcast data are broadcasted, and receives broadcast data at the starting time, thereby receiving a digital broadcast of only the channel selected by the user. Accordingly, the user can view the broadcast data of a desired channel.
However, according to the time slicing multiplexing method of the DVB-H broadcasting system, time slots for channels included in one period may have different sizes, as shown in FIG. 1. For example, referring to channels B and C, it is evident that the size of a time slot allocated to channel C is much larger than that allocated to channel B.
In the DVB-H broadcasting system, since the sizes of time slots are not uniform, as described above, it is impossible to transmit broadcast data in time synchronization between a broadcasting station and a digital broadcasting reception terminal. For this reason, broadcast data broadcasted through each time slot allocated to each channel in the DVB-H broadcasting system includes a time value of a starting point of a time slot of the corresponding channel in a next period, that is, a time value of a starting time point at which broadcast data of the corresponding channel is broadcasted in the next period. By using the time value, a digital broadcasting reception terminal can then recognize the starting time point at which reception of broadcast data of the corresponding channel starts in the next period. Accordingly, the digital broadcasting reception terminal can receive broadcast data of only a channel selected by the user, by resuming reception of broadcast data at the starting time point in the next period. A burst time of each channel, shown in FIG. 1, represents the time value for notifying the digital broadcasting reception terminal of the starting time point of each channel.
When the user desires to change a channel in the DVB-H broadcasting system, the digital broadcasting reception terminal must have information about a time when reception of broadcast data of a channel desired by the user is to begin. Therefore, according to the conventional DVB-H broadcasting system, when the user selects a channel change, the digital broadcasting reception terminal receives a part of packet data of a channel different from a currently-set channel according to a sequence of channels, and extracts a time value “delta_T” of a channel selected by the user. When the time value has been extracted, the digital broadcasting reception terminal consecutively discounts the time value, and resumes reception of broadcast data when the time value has elapsed, i.e., at the time point corresponding to the time value, so that the digital broadcasting reception terminal can receive packet data of only the channel selected by the user according to each period. Hereinafter, such a time value will be referred to as “starting time point information”.
When the user selects a channel change, the digital broadcasting reception terminal receives packet data of a channel following a currently-set channel. Then, the digital broadcasting reception terminal checks whether the received packet data corresponds to packet data of a channel selected by the user. When the received packet data corresponds to packet data of a channel selected by the user, the digital broadcasting reception terminal receives the packet data of the corresponding channel and extracts starting time point information about a starting time point for reception of broadcast data of the corresponding channel. The digital broadcasting reception terminal receives packet data of the corresponding channel according to the extracted starting time point information in the next broadcasting period.
However, in FIG. 1, when the user selects a channel change to channel A while viewing channel B, the conventional digital broadcasting reception terminal must continuously receive broadcasts of all channels until receiving the channel A in the next period via channels C, D and E. Therefore, the conventional digital broadcasting reception terminal in the DVB-H broadcasting system requires too much time for change of a channel and incurs unnecessary power consumption.